Regrettably, the chemical formula As2H4S2 is not a recognized chemical compound. It seems like a random combination of chemical elements. Chemical elements need to be combined at a particular ratio to form a specific chemical compound, and not every combination can result in a stable chemical compound.
The atomic mass and atomic weight of a particular chemical compound also depend on its specific structure. Moreover, the physical and chemical properties will also depend on the specific structure and atomic constitution of the chemical compound.
The chemical equation, synthesis, and applications will also depend on the specific chemical compound. Therefore, it is impossible to provide detailed information about the chemical compound As2H4S2 without information about its specific structure and atomic constitution.
In conclusion, As2H4S2 is not a recognized chemical compound and it is impossible to provide detailed information about it without a specific understanding of its structure and atomic constitution.